The scale of a point of sale (POS) terminal barcode scanner has to be very responsive and accurate at the same time. One of the key considerations for a scale is maintaining a true zero weight before weighing. This true zero can be corrupted if someone presses the scale zero reset button while there is an item on the top plate. That action would create a false state of zero.
This can be an issue especially in self-checkout where the user can be confused when weighing multiple items. Even though the self-checkout provides verbal helps, the customer may not be sure on next steps, and language issues and the rush of shopping can add to the confusion. A consumer can inadvertently press scale zero without a clean or empty top plate.
Assisted lane cashiers are also faced with this problem when they are novice, or just in a hurry. The cashier may inadvertently press scale zero when there are items still on the top plate. There is also a potential for theft if the cashier is trying to remove weight for malicious reasons. For example, selling weighed items to friends or family at a lower value by first removing weight on purpose using the above process.